SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cfb7adc28c25e21c8b43e3aef059d9e79da743b1f65978f68b911b4976f4360' 
  AND token = '0mvFfA9UZsek2SWnmFPZGFoTobYnxj6WeUIx2oxw380=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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