SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '920b919f64099ef8d159cd852cd8dda3cef34cb0bc02a5b54d4c6664c709050b' 
  AND token = 'SU3BGwErTi/MTgsnZbwEWP/xCIH8dNdq3RwNvCt69QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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