SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f58f2dc8c0643503ed51ed913c59d74c5684ebee411902143e665c5df2568385' 
  AND token = 'xqKm6L+iTNu5Si+cxgSBya7HPki1jXNLDLbjKyanLcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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