SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58d581eb65c3f4e20e85cefcd1e8a6bba6d0747d03594df87820d0779963fb26' 
  AND token = 'R/QRSzKBhlZ4Aaii/gP+vl7NCKDZfDw6eHjFKjPl1JQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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