SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '216929f4467f8304150c2fd8408de57edde0f8440d87238e1c3b08e3a946374d' 
  AND token = 'S+L0RxzL8wnJ/TGvUtwEVsBORvFp4D+SITiMDz9uggE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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