SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7de43d868e86d5de301205f4487b4b9d09531b38991f0ae8643a27723039c2f3' 
  AND token = 'qjeyfVYz9NR8HtTtcey6H875vxMhkzrRsxitdU9G6wE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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