SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7f7a18beef9fd8d0b91415f57b36a1e32e131b97f9b218651ea08c73136873c' 
  AND token = 'eGDi45lKvjcjLZdkor9IW0y2qtAHahmDPgb4eB3yOfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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