SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c222c99c0b517adba657ff011dfea621afaaa1616d231be84e41ca3455f780d' 
  AND token = 'QBoTpTYFKctSwnpEJNYOWPb4HiApi9Seuzbqu3mzLkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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