SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4fa1e66c6fb39051fb633b709eb8da53f316099a81a604eefdcef8d886ed9ba0' 
  AND token = 'Q3ChyrFydgm5pthl1Mr75zzyP/7y6wzoRCapayNa0gU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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