SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b63b4e235fa615f8987cdbce375d1df950759224b7fb3ae8b13b89c810933c' 
  AND token = 'EtSZv8U5OCo6+tk4bFEweFSJQSDeou28rVmzY5lKbjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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