SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59c840e98e529db388245db1256fc3a9470881c188b6586f54706f2ecf7f7af2' 
  AND token = 'vW/tjbvIW7qVOE4xbnyvhkgbgvnspXYBjWDZHSJJZA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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