SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93969bd62b0ba42066baa8f673a492fa37820459fa2623fde43c3fada6fcf51c' 
  AND token = '5pkf4vT/H4PR0py3FMETLebbsr7O3DDYuND4l7mHxII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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