SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f6b59a4d2443f42c6f21f4278b03c6f979196338da2e2d392ce8aef91c83af1' 
  AND token = 'SXBNG2/uajrdlx+sCTOqmsVjAMhpr+EYqQvdYXwpOmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}