SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '074e34fb58d042eebb4942053d3493cd80f549585cdf8ebe35bade2aeeadcd4a' 
  AND token = 'XEzBEvnQK/BVlS2mflDTumwhh1nHHMMgMPHhDsWmu7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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