SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df0eaf3d61ec74887d122e5103f642278e00791538a42f13f97f6b2e1ca1a7e' 
  AND token = 'JERX/LV86d2hHHo+4thoguiwU736W6IwY9Rr6KmZhz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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