SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2b4451a5656759dd80da33fd5ca883b4c200a8f3d4f6ff5638416b9f0bc0405' 
  AND token = 'l8MWKFk6kl6oVk2dwpn2AWAtSMnoCu60U9/SJKygspo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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