SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0900d8643c7df3ae7a29cde1f568fb7142754aaa85d759b3ab1a52593d83f08b' 
  AND token = 'N4tDOhZPVArraqpe8ldSVwqMsDkgWXdL3ton7S8L2ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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