SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39450849dc9bfb8bbbd81bf8687a6fd6df7eb63aef3ff60c9b247ccbda48cfc3' 
  AND token = '0h9SNJtPwHtWftSzeSVgRlkvMN4AKa4LDwY2GeLhvpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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