SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40314b230e404d526d402c224d14ba6bd7f2433c53471ac94068bdaf8016e3f3' 
  AND token = 'iJGohMyaECO/OqyJVTHfAtiPIeLnNklVw28AZ1JH0ZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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