SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04b46ad97bddea959ee4e0295237d158544578c2684cef76e85b4806a1af01d6' 
  AND token = 'n+6fiebA7wpH0iQxo+m1gZVMijhDvIryQvWjahGJZKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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