SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa43a8a2a820f929799522f4274a4f21c7438e3d97f0047534dcc024e8d2eb5e' 
  AND token = 'MtoD4pAufTfUOHQbfW5loagtwl4k94ixMS1+fisD/fM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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