SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ebb392934693c7d875a6fbed20d3af880f6e793c42424fec24aba5e2bfad46' 
  AND token = 'W0WAMi2VonutqDAa5wpLZ1IoD7pqK+pvG57R/3sqL54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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