SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb2161d2316752bf9e4ee1a7374e1b0a50eba578f55748563e3499eb392284e8' 
  AND token = 'HAot/offAvwL19PDvxB5NrQ6w0mJ2EwktL/GeTejygY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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