SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '710624494528d9998fd7d30faef170103881278579f3da933a44f4f600f5f023' 
  AND token = 'PimCGjmsvaTpOLnJoKVlhL6vm3Nu6Eh6yHAld+D471Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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