SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e53e4b5cebc554555084dbbad30a74a0fc35f14bb3d126a360a5f45584d69cdb' 
  AND token = 'wX31RsAlJwt1mP3PiWMc4sIxxt6RCg3wGbdqPcMqy4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}