SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bf241bb062019fb5bb8a35947cd260e6588be03413f41f195f27bf524866047' 
  AND token = 'wBFDSwciWCb6DBUc2bg+Gxt3EItnOH8FyRHUh3Ujbo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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