SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12aa124c567ad3e8ee8cccc04d96499e79901cc4ef25d771ea31f50739af56c3' 
  AND token = 'ZCdgjovyMZkRkLYemoUb5MrFrVIh7Ps5rsYPxgLItbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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