SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d477ebffbec290dd6799c77d169abbfc5878b9c9a68fe3d337756e6d39821a' 
  AND token = '5YRCKz/jCUs/7L9Lfa+DzfY3+d+B8O22bInvGKtIw6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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