SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f45cebdcbc57e0103a52e0d70572ada5e9439fb5e650a1fb200c4407e43e90' 
  AND token = 'ec5bGLsCq0hQwCmY8ZThQZFBJ7sikL9i3PpBAs17JcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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