SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a3d714b2eae0fab4647e0a408101a8b389ca02d6d3b90bac1178a9ecac349d3' 
  AND token = 'yT58Kd4brIbGqUU8uDYQJv4IKZ5HYSIbK+90yCKnRYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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