SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdc8a6e6c80006967f2a208cbef9f53dba4f326bb1064a2afb2c161c16ac0cf4' 
  AND token = 'ty347yqGTqvEILcvxYZZw2WE0MtS3fOpQBU1qUq/cvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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