SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0b2d020a305e697820c70197199808e8e34f8bf4a8496be44e08aa078f51f30' 
  AND token = 'h5keeYWfr1T73/a00x0HeLZbFpN9dHEjBgdXQel10tY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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