SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '737226118261ec173111ba04515cafb46b4900fa17d9271a708622251db01ec5' 
  AND token = 'j/9TfWHa4k0SCuTDeES6OxjeUIq1Mf87dc+1ih5Hb94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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