SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfa2f8755b7dfed6c0e00cfa39cbd710b43733386b7432a99625a2f5c901e8fc' 
  AND token = '/+MOcUZXZTYoUJwtds2JWemTshSIniOkDyOMrm4bqF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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