SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73ce414f53a9f30dd177d02f25d0fcc6c34079acafec61ae76fb382495a8779c' 
  AND token = 'TzlvQHH8FBv5q3/SHddrF/3MWFjbFY39RzePiAvklG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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