SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7498bb0b744a509458319428a466b33330c28887ee3f3ea6cccb940f357544dc' 
  AND token = 'YKvpMI9aFIVRGrbGfioWKnio5HxqIMkfLJymLI+JeRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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