SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce9a4ad31c92ac605db68811fffc8d3308d1aa519416b7adc1e3b712c1835337' 
  AND token = 'zurg8KoUsKhLpJ49hzDJlP+4q3YgRJ76704byZUrmRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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