SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90717bd87af75d603508d1b03dbd269dc8d5a300032e589dc81734479e44fb5b' 
  AND token = 'VQSVWYeHvMlwXdLyaeryDAjXcJfIP540OtJoJHOntDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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