SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19940e7f9ec2b97b21fcdf04d25fa91159b9b5fa1cdb21b04d3fdeb77a5bda60' 
  AND token = 'BU4ZdSCnNBBBOXFuNXs6VHEJropFCI95UxQ1LgqtpTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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