SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f6d5321724b1108a8792a989516f7fded39548a17adfdcf5cb2300f3332472e' 
  AND token = 'bZnNW1GBeI6UtCoLYrCFJ/UzIxk+B3rpChWfiiZ8aKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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