SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71554b80e831b98d655555da04b7711d9bc6dccf5b35913f266098a6f9bf38c4' 
  AND token = 'z7j/013U8pTwIESKYsvVE20+BvBoGCRbYp58LLdOBko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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