SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108c606df402872a36f3403a86f8c922195b7b9ae7dc33c955a71ca16bad3b47' 
  AND token = 'qYH+OwTTHTjiOB2+DOPaI6q+LKj0MGnSs5zs6VXkQEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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