SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a31f95eb4eed3fa36a5fb0172c14b75e423fe8a60863659649fa3a72d76e193a' 
  AND token = 'tqoWDm/IzpCIhbjhnStUA4tUnrFso+XhiyU0nwUkYgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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