SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79b6fbb770f5b7324c35f052652202543fd0abd63b4247ffc044408cb3b7da4c' 
  AND token = '3EGXlxVsB5hIcDqyCHl2901Cl+GaesXpBnc9JBLIu9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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