SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c311b0afd251c05fedee4234f9c51aaf594f11399ea7f598a098ae1951d64239' 
  AND token = 'zuVrSLNOBzyfo2fyQ4wa2pvZxMy6oBHL0C91erDEtv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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