SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f26d53ce9071dd02e7ec7b6922a6f175105504de5836c731d669a90ae490364' 
  AND token = 'XYrfBvMhpPQgzOSzSJzVFtJ02hV+HqEAb6zxsy51hjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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