SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1774ae8fe217baac5858e4a52fc1981bcda5c4701a228270e940f3eeaddbe4a' 
  AND token = 'TWBgtWRrJ17EpvUnvlCJg+u0tD8GwLYWxk0huuuK8T4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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