SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dfa1461ccb229535f0de78cc830ea947172884b1ba5d0192b20cd3f57cb8bfc' 
  AND token = 'rsLT9c10UkSAg/1q6zpJz9Dya5dBf7JoqtMDCghZKVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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