SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '615451fd68f32b95d1373ba6ef99eb808892836ccd1257597cdca991ad0f6d7b' 
  AND token = '/zpvt2vsvrzcZ64z8mVxWzeSPK9lA0JqxyCXTTvxPgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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