SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce3bc2b8807906eb8f7c70bba89d12714b0a4aebaa760a3472f091462ae4fae7' 
  AND token = 'fOUbqwY8VuAzKt3eQ57eBr4mejm3EvEPYOQs+n7pnp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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