SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6493cef92d255f470020e7af0d1e3a2622f46bf696057f92fb0d544e27e3bf57' 
  AND token = '3qhviwuCc+aPPpOwdbB2brnE+AlOE6ZqMP4mhARyEqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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