SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a64b7360e11a7a8a690c530e84cddc97054bf888c754847a1f2dc8cfb0cccf04' 
  AND token = '1r6dwOgc2x2nnKDo/SJ8uUIBToR21Y0WnbnPUczojZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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