SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8eae1eb5c3f4721849d95f6d4d48acbef61e2f75708465beb36a7e3f59cc37d' 
  AND token = 'OFPBTIEliaQH6ho8DlJT2zf4OMjmwn6TYmL8DUIJbJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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