SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6643724883204ed1bc22b915e53aa6882bcce4b150319dffde566dbdd2eefbbc' 
  AND token = 'kOuFbXTF1jX+TI8Nadg7Hp4YMOXTrJo4LyK9WkKt6PQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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