SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4da6e33a36242edbaddd552f77c669a4bb43d735fb046689af242e0edb670991' 
  AND token = 'P/CTdnG9YuvgoCZDZWRGr0/wUtyFx7g+iBfKCoFM9TY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}