SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956e1b5e1c322802265da40ecb83a20217090f14b30bb15864d4ab70dbd844e4' 
  AND token = 'd+VsGCpKhvLD3gZxUIquXn53N1I/DUCDREQlYD+kiTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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