SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ca728be9d2bf5a7a08bc9fcfcfb4094371c755ec20397f60f67e425da9395ba' 
  AND token = '1D9NrmdmBRW8TtDLiFhhLrsJhnKbRbDJPeIhgSLW4KU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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