SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4949050cce07f8174d0dae312a5d5fd9db504a2dbe622752d37ebbed5ff25912' 
  AND token = 'KhRIEQmkU6eU1LmMxWPC2aYxBiPcp0VV+qKpqwi5V8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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