SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e8fe52076a28f17aef67ecc806073e29a1a4b2f304bc958bf8cd2166434e471' 
  AND token = '4V6Q5lPVt0iY809Z/C6oobeQIz8V/RYodF4Qau2YpKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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