SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc94d54af16b4abf7fe4261c297fa9eacaec33efdcc779ea1798402e4502dd91' 
  AND token = 'uxPfG7mycBMg9S8DUSQmqiXcv2zQtdvf7M/d0kPrRys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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