SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd731ed8ea36dff27249f62d0d6e41b6d9209bf1ee5341437179c12482c32de5' 
  AND token = 'lb4dBtvKNLzeOLbcSgU9AeMIvx1xFwmp++eLLhXPApk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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