SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e14ae5c5e2c64264f1b2c61d4b058354cec675b83c9db93e71983353ca161ab3' 
  AND token = 'y/HbF1KMvFC2CLPHBhb+JisBhPfVght+Hqz1wRd0ZIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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