SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a665e305fd657f9033fbacf6141f9023c32953c7f48ffb0c09c76e1c031d6d62' 
  AND token = 'uOVBmDmCIpRvK3uYTTv5JusxGM2k/ezoec7lTrgkiao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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