SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99f8653bad3891459f203a1ffd391644d32c94bc957b0fdd6284e40d74a2d6fb' 
  AND token = '6gFxRfsD9R9NXiqgdIHKwdZTvUkfvZkN58VjB8CHbqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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