SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '905b4fb61b7b1371617bebfe4357be019ee5a9c9c4c54161edcb9144996d8624' 
  AND token = '+V+qQceRBoE2OVcGCeBDeC45U46CKmjTehoJysGr6Rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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