SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf2544effdd52dc630233cc82d15a7b62c0310c95677448dd3d6e1f8df942360' 
  AND token = 'URwsFokKy4djPXkeMb/+DIxMBkkVg7wbpMkZ9wt/z/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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