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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fcbc6af095dcc9c56951f82d4ed0f6df90d4b642e58446ca9e1c95cbfae4e58' 
  AND token = 'sCMTWqX1SXZ8nPv45LDVAdi/8VxE+1meBeAG0e/KQWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}