SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c661b92df8090d5031906e0a28c215a21705ff812d0aaa990be239b120dfdd1e' 
  AND token = 'swRQ6keHhvyQGCXrEUe8TG6pxr0jbhkNuEegYEkrWNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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