SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b82402e136ede549e46593faae26aa01efa1ab8870555d16a05fda4caaf3d81' 
  AND token = '8aEcJDv8gOdf0qoqbOKkbgqBGb7RaYDaN1R8IK9d1KI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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