SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e824a385fe579fdb23571e9a990f2293c08074882855766621be316e3472e9c' 
  AND token = '+8oFMGZL5FCsmSWjh2kdn/FuCn9zva1RFlyT10PJ2r8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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