SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af5079258e45db3c225a729d48f105818954b2c93902d6782d11b1893aa4db78' 
  AND token = 'ZWVGrqqB08M10ZOU1QRRI1lF79chV2EBaz4KhaDFAZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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