SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e76b83a53770912a42f78f415760b214a4d65c67af90345e06a88cd917614e9b' 
  AND token = '6wIQlFC356GhlFQwKPaYyoJ3x6iMj3cxZiwwzgYlyGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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