SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b013ac7c0f96a658646571104444246b5c7ba6253417352973bb474b75d45c7b' 
  AND token = '5JuCnSBmPaJa7JOwuiEntKjpR1XCjQ90wfjXtV522RI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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