SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad448103b56d940aa60576f1efeb84ee05dd5dfff03a672dd7faf7f6fa2fa460' 
  AND token = 'vJWdWZ+4hit9aviLTTRyLP/cvvfuZJIF0bl/4kiI1IA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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