SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ccef331b36dce902afd871ab0fff83eb02917b0bd5173d05366da7a05e90627' 
  AND token = 'zKL8bon+eJQ0f/aLbWMi2FWOD/z+KghqWQKV/apxOFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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