SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b0c900f5ecfe3995d8e38efa60a9e6b3f69311ddd7e861ba72ce9bbe8fcafdf' 
  AND token = 'BmiEQ8ZrFcO1BjMO0d4dFtrUHnnP6uWpU9SAmSBwmJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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