SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d6adfbf75a504703cb558f884f375d509ff56447482864cb4c6a636d994ab0' 
  AND token = 'rz2m/YOYlrvJjy/QGaIEwAakhvHHSlgJqNrR1XQZEdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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