SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbbfa86a85f8e6085946f4421b09041aa74cd9d57172c6f61c690d762b2e4477' 
  AND token = 'a+DommlI7ielusVcstAjy4WNJAvFipnkJAovUoKuaEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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