SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43da14da9552778767200ca3c99ef41b945847eb394f246a20bfde3e5efd39a2' 
  AND token = 'wj/2ELZNBJAzQBkDFZ1x+lEyid+1BK+f1sqxMeHU948=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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