SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6823504d4ec5c7ccda8db9c137a98d4ec5458354f37c80ed480545b44480c5b9' 
  AND token = 'KUZBKOW4rQM/adVNvCeP1l+4KVt31PamajqQpvs+/Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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