SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b038518250f96103b520afb00cd3514be3b4b0b4ebba97926bec6c4022ab677c' 
  AND token = '1GeEP7gBGnjDxmGJgeXTJ5cJGoiPqlLu+q59dJWzxEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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