SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d706d7ba2717d82c8a845d36837b30b3cff8d9b1913b78f4fe74fc15b99cc75' 
  AND token = '4d7nZS7dV/A7fXyhQeTapgiFVPnreK34GAFXY5pBSDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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