SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2f0674201ebd08eca3cf64b5fe112c1e239bc414c79d61afd277d32fca71509' 
  AND token = '4lK46fwnc/XG7g/yIzOazx/fzIWPklJOtcQADrBtRXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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