SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4746366c16dd2ef1cc52f3cf2af83184877af78bed4f98a0c7a623e1252d035' 
  AND token = 'vZuaLbgeFmoD9eq9AlmBTRO3gQy5oGf0Q0au59UMy/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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