SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea78477d249c0ab74583a2ffceae15b84763518319e50ca4bffc5123e7a2b644' 
  AND token = 'FYc6WD7cz6Ibu2w7uUkKBmqNfo9Yo43T/pCfYdeUqPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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