SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b64767f72e167644d550c5de1cd69a0f257262716c17b339b30d09c52cce0dad' 
  AND token = 'EJPxfeShCFzqfLVt/qys6f8Ac8cGyS2KChCf5ph8Erc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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