SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e71bb4fd1ed93483bd8445e69c663adb82cc2ce6f01382e13fe57020deb9cf3' 
  AND token = 'pt0xjWZSYRXOMcZMSG94IRY/0jEmXeEdQApJ/ODia78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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