SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6d9360201a2f433d0cb86ef1ac94f9393e039b5575a4afe40780758c1273955' 
  AND token = 'dK4GzsmKDD4upuyCQSdf5QjOe5uadi8nrfvBxLmm0Es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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