SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c38a3196346cf5eb08ec82f821a39ec433002de2a2c97625b228383272d0b7a3' 
  AND token = 'em5u7euJu++fTCqcnFfpiILsLj8YXW5yg4uz8jdFmwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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