SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adc6b5ecb65fc12b42ecbb020faffc65b39e5085028d9f10bfe40d2e47a6e701' 
  AND token = '2dkW4FNz62PT1UywymlLBQ6tpA89Z/DRputrpGfM834=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}