SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '66f1657c10bc81cad8b4704e38f945660e5932498ff89dda7c0bffb2529b53ce' 
  AND token = 'fHI99MFlD9epEesCh1IqRls1zfJ+yIzrCKNSKa6egMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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