SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb7723b05f18ed8d51dc473623f032fc508dbaacb3c4b17b70122777ba975770' 
  AND token = 'LhgovQGO5+uXLzJKKNot4WYfWGLCrs3BCtkaCaaVKWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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