SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f9e3708a770280e686b17fda3ae79db5d0d88b5be6e7f00939f32ccf95d1bb6' 
  AND token = 'mPKxlq4GZsiVOaqZPZpDelidR0hDX4AM3sW1aVj9yp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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