SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1243561ea46104e8a5dc0fb336237b82196374141189dfab9aafc3d4fdcc0091' 
  AND token = 'kEbY4InxOZkxeEEiB+7mUZl0cq6GWqlJiRyBsRMd2jo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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