SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f94008fa0a1ec95c685235abfc59edcd04015f7afe1681288dae6d5d8f272a6' 
  AND token = 'M2V6g7+XxDP1HpJni9ZxJhc6BuHYQOtlXf1zsDiCq9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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