SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '989e88b241f0f30ff85c049d137c702447dfb1199ceeb689002b9ffa2e46a747' 
  AND token = 'n9vvF/fM9USkUOyMrvnfD6kVyWQ6IYxXsc/stK48LDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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