SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2ad3d8cc196943d33d91674f10fa35aba95adf437c402657f993f685e044399' 
  AND token = 'qKBtk2z7GnUSiPFSssn3dMSHahX90c80KlSkUDI6QQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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