SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1092dc00fabc7bd07a89daede1ddda7df0685cf858f996c47703e3d64f528ce' 
  AND token = '6ziv3AdYhksuk3ZxRzkwGNRJnbAKpvkIzi+WVyqAMlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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