SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea7218f33001023634dc794cf80fa69916d264378489fda5c5d37ffa44d1d463' 
  AND token = 'ao8DSmbQtCRAvzJym1nvg2s7OqAUt9yjNuaLhZCU/b4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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