SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84ebff18093a798db555eff0c36b6a2957dccd2ede964a9283c474f3e59cb2b3' 
  AND token = 'VWpYVLPVYTg+NSTxbhIwk7Cm8K5iNJPWYxXEE+C31XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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