SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe2ceb03939f667077d677ee55c16135d436c76848374d78c9239b638e955c86' 
  AND token = 'YCPBAqf3CZUWOGZbns+0e6TFK3d/7XAmL/gJ+0VHT4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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