SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc636d4ad7366c5836e55bef024377b7510006b7829821649b87d9e782e61a5' 
  AND token = 'ApiexRBTlBB8XOMtMppOGl2RclWUVPoC9NTYCij1UbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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