SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7796fd7f76b2db54072a662ccd4eff64396592872d02949dd04cb9f7fa8e1df' 
  AND token = '61QipSFRUaIcxZpjhyAqN2LwOT6O3MzOsCYuSAy3t3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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