SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76426595cb76e0b65aeb5560031ddc13f260ae56ae6b55abc03dd2fa599d802f' 
  AND token = 'WwOHBPjvtFXcIoQRtkxaywB1KUpFXjqrbTc/r5atXFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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