SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43cba8beb2bd4771ace0c0374ad602291cc2699dbe08199e12095acb5e2bc3ad' 
  AND token = 'q8dKYIow9vY897NcOOUBpTEb61aF5wmM0XcFatw1tJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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