SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3114b33412965816153d8819589147194cc291722298d375782669c184abf74' 
  AND token = 'cOBqnYtO2D+hodvaZfKHJusevxu0b67WzkmNUMoh9rQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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