SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '866873d369e2e00a1f89cd263fcbf596add37d2026c12e6502e742fc78958aa8' 
  AND token = 'FYrByIlaDG3jjlzbO/BbjKCpMvGmL+BDQSObjMyziyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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