SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da45a50f7ff30db9b7c3a344bdb23a45e76d42c290fe13ab3d0e322302cacdd0' 
  AND token = 'wUD1gMuDnvYubXdzaAJPcuWhXKUY2hG00r9cJcm5Hfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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